A civilized nation, Ukraine, suddenly starts to come apart, with newly formed “militias” roaming the streets and declaring themselves part of a people’s republic.

The French philosopher and journalist Bernard-Henri Levy had a stab at answering that question in an op-ed piece he wrote in The New York Times last week.

Russian President Vladimir Putin, he said, had “mobilized the worst elements to be found in the region.”

“He has taken thugs, thieves, rapists, ex-cons and vandals and turned them into a paramilitary force. ...

“He has watched as a vodka-soaked rabble army destroys or takes over public buildings, hospitals, schools and municipal offices of the country it is pretending to liberate.

“He has allowed a veritable gang war to take hold. ...”

It has often been an astonishment to ordinary people how Adolf Hitler was able to empower a sufficient number of people to carry out the massive evil that he unleashed. The only way he could have done it is by marshaling “the worst elements” — the thugs, thieves, rapists, ex-cons and vandals. Give them uniforms and sinister emblems, teach them a special salute, spread fear and play on the hatreds of ordinary people, and you will have a movement, maybe a party.

Could it happen in America? Imagine if a charismatic figure could somehow weld together the Ku Klux Klan, the Hell’s Angels, and the Mafia, along with the most recent incarnation of organized crime, a Mexican drug cartel. Give them a political agenda based on hate and give legal sanction to their violence, and you have elevated brutality and sadism to official policy.

It was not so long ago that the KKK had more or less official sanction for their reign of terror in the American South. Why was it next to impossible for many years to enact an anti-lynching? Because lynching, among other tools, was how white supremacists maintained power.

Genocidal sadists, backed by the United States, were responsible for repression in Central America in the 1970s and 1980s; genocidal sadists rose to power in Serbia in the 1990s. It is not the nice people who do these things.

Levy accuses Putin of playing with fire by creating an underworld of “undisciplined louts who know only the law of the jungle” and by giving them an arsenal of deadly weapons that they used to bring down Malaysia Airlines Flight 17, and a number of Ukrainian military planes. The Ukrainian people want peace, not gang warfare, and yet the eastern part of their country has been put in the hands of clueless thugs whose actions have spun out of control.

Levy’s point was to draw a clear picture of what is happening in order to delineate the moral consequences. He noted that the Ukrainian president, Petro Poroshenko, had reminded French President Francois Hollande that the world had blacklisted Muammar Qaddafi for blowing an airliner out of the sky over Lockerbie, Scotland. His point was to shame France into refusing delivery of two war ships it is building for Russia, a decision that would have pecuniary consequences for France but which honor would seem to demand. Other European powers are talking tough but have shown themselves unwilling to create economic difficulties for themselves. Levy said they are exhibiting the “spirit of Munich,” and he called it a disgrace.

World War II analogies should not be overindulged, and Levy is a well-known intellectual peacock, but his analysis of the character of the separatist movement in Ukraine has the ring of truth. All societies have their underworlds, their thugs and sadists and crooks; civilized societies find ways to marginalize and contain them. When things start to come apart, exploitative politicians sometimes find uses for them or go in league with them. President John Fitzerald Kennedy sought to enlist the Mafia to kill Fidel Castro. As Putin is doing, he was playing with fire. In Ukraine, if the West doesn’t seek to marginalize the criminals, who will?